Explosive composition



patented July w th pair eras filtth ttt Ft-E 2,-Si25,t5

EKPLQdlli/E EQMPUSHTHQN litobert W. Lawrence, Wilmington, illicit, assignor to Hercules Powder ilompany,

Wilmington,

lDielL, a corporation oi Delaware No Drawing. Application November 2?, 19%, Serial No. 367,381

(ill. 52 -5) 8 Claims.

This invention relates to explosive compositions containing a nitroparaihn as an essential ingredient thereof and particularly to an explosive composition containing nitromethane and nitric acid.

Liquid nitrogen tetroxide explosives have been known for many years. Such explosive compositions usually comprise mixtures of liquid explosive compositions normally contain high proportions of a low boiling constituent which renders them difficult to handle.

It is an object of this invention to provide an improved explosive composition containing a nitroparafiin and nitric acid.

It is a further object of the invention to provide an improved explosive composition which i comparatively pleasant and easy to handle.

It is a still further object of the invention to provide an improved explosive composition which does not appreciably interact chemically when stored.

A further object of the invention is to provide an improved explosive composition which can be readily detonated by commercial blasting caps but which is only slightly sensitive to impact.

Another object of the invention is to provide an explosive composition having a lower freezing point due to the inclusion of the nitromethane.

Further objects will appear hereinafter as the description proceeds.

The objects of my invention are in general carried out by providing an explosive composition comprising a mixture of nitromethane and nitric acid. Other nitroparatdns may be used and preferably those having the least negative oxygen balances such as s-dinitroethane, 1,3- dinitropropane, etc. i

In accordance with apreferred form of the invention I mix a liquid nitroparamn such as nitromethane with concentrated nitric acidin suitable mixing equipment to form a solution. Such mixing equipment preferably includes a cooling coil or jacket to dissipate the heat of solution. .Any suitable cooling medium such as ice cold water or cold brine may be circulated in acid-proof containers, such as, for example, plastic, glass, coated metal, etc.

By Way of illustration, I have shown in Table 1 four examples of nitric acid and nitromethane mixtures, one example of a nitric acid and nitroethane mixture and one example of a nitric acid and l-nitrobutane mixture. The compositions containing nitromethane vary from 15% HNO: (98%) and nitromethane to 63% HNO: (98%) and 37% nitroinethane. Oxygen balances vary from 24% to +2i.7%. The explosive mixtures shown in Table i. all detonate with a brisance which is approximately equivalent to that of nitrogylcerin and can be satisfactorily detonated with a commercial No. 8 electric blasting cap. For example, the mixture ofnitromethane (61.2%) and HNO: (38.8%) has an oxygen balance of 0.0%, a density of 1.24 g./cc., and a detonation rate of 6650 m./sec.. It is to be understood that the proportions of nitroethane and l-nitrobutane may be varied with results similar to those obtained with nitrornethane.

Table 1 Examples A B C D E F BNO; (98%) .per cent 15 19 6C 72 Nitromethane. "do" 85 81 Nitroethsnedo.. lnitrobutane do. Oxygen balance d0.

It has also been found that the nitric acid nitromethane mixture may be considerably diluted with water and still provide an explosive composition which will readily detonate. Examples of these explosive mixtures are shown in Table'2. They may be detonated with a No. 8

electric blasting cap and have a detonation rate approximately the same as that of a gelatin dynamite.

1 of-ENO; 35.3%, Hi0 6.7%. OE-HNOB 33%, E20 14%.

Too much dilution of the nitromethane nitric acid mixture will, however, produce a; mixture which does not fire with a No. 8 electric blasting cap. Table 3 gives the results of four tests made on compositions using a constant ratio of nitric acid to nitromethane, i. e., 0.627 to 1 and in which the percentage of water was varied from 17.3 to30.1. It will be noted that the compositions containing respectively 17.3, 20.6 and 25.4 per cent water shot with a No. 8 E. B. cap while the composition containing 30.1 per cent water failed to fire.

While generally speaking, strength is developed by explosives whichcontain just suflicient oxygen to convert the carbon to carbon dioxide and the hydrogen to water, excellent explosive mixtures can be obtained with positive and negative oxygen balances. Thus mixtures, of nitromethane and nitric acid varying from 85% nitromethane and concentrated nitric acid (98%) to 37% nitromethane and 63% concentrated nitric acid (98%) form powerful explosives. (See Table 1.)

It is to be understood, of course, that nitroparamns other than those shown in Tables 1 and 2 may be used for the purposes of the pres ent invention. Thus, for example, 1- or 2-nitropropane, primary or tertiary nitroisobutane, symmetrical dinitroethane, 1,3-dinitropropane, either alone or admixed together may be used. I prefer, however, to use nitroparaflins with a relatively small negative oxygen balance such as nitromethane whose oxygen balance is 39.3%.

Explosive compositions according to the present invention will be found extremely useful in quarry blasting and open-pit metal mining where a powerful explosive with a high rate of detonation is needed. These exposives are also useful for various military purposes.

My explosive compositions are advantageous in many respects. chemical interaction under ordinary conditions of storage. They are generally pleasanter and easier to handle than the more volatile nitrogen tetroxide explosives. They are only slightly senthe maximum,

Thus, there is very little sitive to impact though readily detonated by commercial blasting caps thus being safer to handle, while having at the same time a high detonation rate. They have a lower freezing point than prior known liquid explosive mixtures and are very simple and easy to compound.

A further advantage of explosive mixtures according to the present invention is that the nitric acid readily forms a solution with the abovementioned nitroparafiins in contrast, for example, to the petroleum hydrocarbons, such as hexane, which are not miscible with nitric acid.

It will be understood that the details and examples hereinbefore set forth are illustrative only and that the invention as broadly described and claimed is in no way limited thereby.

What I claim and desire to protect by Letters Patent is:

1. An explosive composition comprising concentrated nitric acid and nitromethane.

2. An explosive composition comprising concentrated nitric acid and nitromethane said composition having an oxygen balance between about '25 and about "+25%.

3. An explosive composition comprising a mixture of concentrated nitric acid and nitroethane.

4. An explosive composition comprising a mix ture of concentrated nitric acid and nitropropane.

5. An explosive compositioncomprising con- U 1 centrated nitric acid and nitroethane, said comnitrobutane, nitroisobutane, nitropropane and dinitropropane. H

8. An explosive composition comprising an admixture having an oxygen balance between about -25% and about +25% and composed of nitric acid and a lower nitroparafiin selected from the group consisting of nitromethane, nitroethane, dinitroethane, nitrobutane, nitroisobutane, nitropropane, and dinitropropane.

ROBERT W. LAWRENCE. 

